Embed MS Excel in SWF / Silverlight

For a project requirement, I want to make available editing of an excel file through browser. The only possible ways that I could think of was by embedding the excel file either in Flash or Silverlight. I am building my project on asp.net mvc3 c#.

I wanted to开发者_如何学Python know that is there a way by which this could be achieved? I shall be happy to start an open source project is need be so that people who are interested can collaborate together.

Any pointer would be great.

Much thanks.

---

Well on Windows Live Skydrive there is an Silverlight Excel app, but that requires windows live accounts... There are other controls out there I'm sure, just most will cost something.